NEW YORK—The Cooper-Hewitt National Design Museum will begin work in January on the renovation and expansion of its Fifth Avenue Carnegie Mansion, the New York Times reports. The goal is to create more space for ambitious exhibitions and for displaying works from the permanent collection by increasing the museum's total exhibition space to 17,000 square feet.

Though the estimated budget for the project has jumped from $43 million to $64 million over the past year, museum officials say they have already raised $37 million. Of the total, $10 million will go to the endowment.

The renovation was designed by Gluckman Mayner Architects in collaboration with Beyer Blinder Belle and calls for a new 7,000-square-foot gallery on the third floor, where the museum's library is currently located. The library will move to one of the two adjacent town houses owned by Cooper-Hewitt on East 90th Street.

The museum's administrative offices will also move to the town houses, and its digital photography studios and decorative-arts conversation lab will all relocate to a 25,000-square-foot storage and conservation space in Newark, N.J.

Twenty percent of the permanent collection will remain on-site.